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Java > Open Source Codes > org > objectweb > dream > util > EmptyIterator


1 /**
2  * Dream
3  * Copyright (C) 2003-2004 INRIA Rhone-Alpes
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this library; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  *
19  * Contact : dream@objectweb.org
20  *
21  * Initial developer(s): Matthieu Leclercq
22  * Contributor(s):
23  */

24
25 package org.objectweb.dream.util;
26
27 import java.util.Iterator JavaDoc;
28 import java.util.NoSuchElementException JavaDoc;
29
30 /**
31  * An empty iterator implementation. The {@link #hasNext() }method always
32  * returns <code>false</code>. The constructor is private. As a consequence,
33  * only one instance of this class exists, and can be referenced using the
34  * {@link #INSTANCE }constant.
35  */

36 public final class EmptyIterator implements Iterator JavaDoc
37 {
38
39   /** The only instance of <code>EmptyIterator</code> */
40   public static final EmptyIterator INSTANCE = new EmptyIterator();
41
42   private EmptyIterator()
43   {
44   }
45
46   /**
47    * @see java.util.Iterator#remove()
48    */

49   public void remove()
50   {
51     throw new IllegalStateException JavaDoc();
52   }
53
54   /**
55    * @see java.util.Iterator#hasNext()
56    */

57   public boolean hasNext()
58   {
59     return false;
60   }
61
62   /**
63    * @see java.util.Iterator#next()
64    */

65   public Object JavaDoc next()
66   {
67     throw new NoSuchElementException JavaDoc();
68   }
69
70 }
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